Lancing device, method of making lancing device, pump mechanism, and sucking device

ABSTRACT

A lancing device according to the present invention includes: a housing; a moving body movable relatively to the housing for forward movement of a needle; a driving mechanism for forward movement of the moving body; a hollow pressing portion at a front end of the housing for contact with a part where a puncture is to be made; and a pump mechanism capable of causing a vacuum to act inside the pressing portion. The pump mechanism is capable of adjusting the vacuum. The pump mechanism includes for example: a moving portion capable of reciprocating in a first direction and a second direction away from the first direction. Preferably, the adjustment of the vacuum is made by changing the number of reciprocations of the moving part in the first and the second directions.

TECHNICAL FIELD

The present invention relates to a lancing device used for sticking aneedle into the skin when taking test samples of blood, other body fluidor tissues, and to a method of manufacturing the lancing device.

The present invention further relates to a pump mechanism suitable forcreating a vacuum on the skin, and to a sucking device for sucking onthe skin.

BACKGROUND ART

Conventionally, a lancing device of this kind is disclosed in theJapanese Patent Laid-Open No. 11-9577 for example. The lancing devicedisclosed in this gazette includes, as shown in FIG. 31 of thisapplication, a generally tubular housing 90 and a lancet holder 92holding a lancet L. The housing 90 has an end fitted with a tubularplunger 93 having a check valve 91. Though details will not be describedhere, according to this lancing device, when the plunger 93 is pushed ina direction shown by an arrow Na, the lancet holder 92 latched at apredetermined place in the housing 90 is forced to unlatch. Thus, thelancet holder 92 is propelled forward by an elastic force from a spring95 toward an open front end 90 a of the housing 90. Though notillustrated, the front end of the housing 90 is pressed onto the skin,and therefore the forward movement of the lancet holder 92 drives thetip of the lancet L into the skin.

Once the lancet holder 92 has moved forward, the lancet holder 92 isreturned by an elastic force from a return spring 94. Likewise, theplunger 93 is moved back to its original position by an elastic forcefrom a spring 96. This causes a volume increase in a space 97 in theplunger 93, creating a vacuum in the housing 90. A vacuum can also becreated in the housing 90 by returning action of members 98 a, 98 b.Therefore, if the front end of the housing 90 is still pressed on theskin, the skin comes under the vacuum, and bleeding is promoted from theplace pricked by the lancet L. The check valve 91 closes when theplunger 93 returns, thereby helping the generation of the vacuum, andopens when the plunger 93 is moved forward, to help smoothen the forwardmovement of the plunger 93.

However, the conventional lancing device has following drawbacks.

Specifically, there is personal difference in the volume of bleedingfrom the place pricked by the lancet L. Also, the same person bleedsdifferently from place to place; some place bleed easily while someothers do not. However, conventionally, the level of vacuum created inthe housing 90 is more or less the same all the time. Therefore, fromtime to time depending on the vacuum in the housing 90, it is notpossible to obtain a sufficient amount of bleeding, or the lancingcauses too much bleeding.

Another problem is that conventionally, the vacuum can be created in thehousing 90 only after the lancet L has been shot to the skin. On theother hand, when lancing is to be made on a thin and easily relaxingpart of the skin for example, it is sometimes more preferable that the avacuum should be created first to suck on the skin, before shooting thelancet L. However, this is not available in the convention, and has beenan issue of inconvenience some times.

Further, users of lancing devices are often clinical patients or theaged who do not have physical or bodily advantages. Therefore, thedevices should preferably be very easy to use.

DISCLOSURE OF THE INVENTION

A first aspect of the present invention provides a lancing deviceincorporating a vacuum generating mechanism, comprising: a housing; amoving body movable relatively to the housing for forward movement of aneedle; a driving mechanism for forward movement of the moving body; ahollow pressing portion at a front end of the housing for contact with apart where a puncture is to be made; and a pump mechanism capable ofcausing a vacuum to act inside the pressing portion. The pump mechanismis capable of adjusting the vacuum.

Preferably, the pump mechanism includes: a moving portion capable ofreciprocating in a first direction and a second direction away from thefirst direction; and a pressure chamber having a volumetric capacityvaried by the reciprocation of the moving portion.

It is preferable that the adjustment of the vacuum is made by changingthe number of reciprocations of the moving part in the first and thesecond directions.

The pump mechanism includes for example: a cylinder and a plungercollectively providing a pressure chamber capable of communicating withan outside of the pressing portion via a discharge port and capable ofcommunicating with an inside of the pressing portion via an intake port;an operating mechanism operated by another action than for the drivingmechanism, for causing one of the plunger and the cylinder toreciprocate relatively to the other; a first check valve capable ofopening and closing the discharge port, opening the discharge port whenthe volumetric capacity of the pressure chamber decreases; and a secondcheck valve capable of opening and closing the intake port, opening theintake port when the volumetric capacity of the pressure chamberincreases.

In this case, the discharge port and the first check valve are providedin the cylinder or in the plunger for example.

Preferably, vacuum generation by the pump mechanism is selectable fromwhichever of before and after the moving body is moved forward.

The pressure chamber, which must be communicatable with the inside ofthe pressing portion, may be provided outside or inside the housing.

Preferably, the pump mechanism further includes an elastic forcegenerating portion storing an elastic force generated by the movement ofthe moving portion in the first direction and moving the moving portionin the second direction by releasing the elastic force. The vacuum isgenerated by the movement of the moving portion in the first direction.

Preferably, the driving mechanism includes: a first engaging portionprovided in the moving body; an elastic portion for forward movement ofthe moving body, for urging the moving body in the forward direction; asecond engaging portion for engagement with the first engaging portion,for latching the moving body in the housing; a lancing operation memberhaving at least a part thereof exposed to outside of the housing; and anunlatching portion to act on the engagement between the first and thesecond engaging portions thereby unlatching the moving body uponoperation of the lancing operation member.

Preferably, the pressure chamber is provided by a cylinder and aplunger, communicatable with an outside of the housing via a dischargeport, and communicatable with an inside of the pressing portion via anintake port. The cylinder is movable relatively to the housing, and theunlatching action by the unlatching portion to the moving body isactuated by direct or indirect pushing by the cylinder on the unlatchingportion.

The unlatching portion may be fixed to the lancing operation member.

The cylinder is fitted reciprocatably in the housing for example.

Preferably, in the lancing device according to the present invention,the inside of the pressing portion communicates with an outside of thehousing when the lancing operation member is operated further, after themoving member is unlatched.

It is preferable that the lancing operation member is operable under asmaller resistance before the unlatching of the moving member thanafter.

Preferably, the lancing device according to the present inventionfurther comprises a pressure reducing operation member for movement ofthe moving portion.

The pressure reducing operation member reciprocates with respect to thehousing for example, and preferably the pressing portion is rotatedaxially thereof by the reciprocating action of the pressure reducingoperation member with respect to the housing.

Preferably, the lancing device according to the present inventionfurther comprises an elastic portion urging the moving portion forreturning reverse movement. The elastic portion is provided outside ofthe pressure chamber.

The second engaging portion is provided, for example, in a latchingmember fixed to the housing and providing a housing space for the movingbody, the elastic portion for forward movement and the elastic portionfor reverse movement.

It is preferable that the drive mechanism further comprises an elasticportion for reverse movement of the moving body, in series with theelastic portion for forward movement of the moving body, for supplyingthe moving body with a reverse moving force after the forward movementof the moving body.

A second aspect of the present invention provides a lancing devicecomprising: a housing; a moving body movable relatively to the housingfor forward movement of a needle; and a driving mechanism for forwardmovement of the moving body. The driving mechanism includes: an elasticportion for forward movement for supplying the moving body with aforward moving force; a first engaging portion in the moving body; and asecond engaging portion engagable with the first engaging portion andprovided in the housing. In addition, the device further comprises anelastic portion for reverse movement of the moving body placed in serieswith the elastic portion for forward movement, for supplying the movingbody with a reverse moving force after the forward movement of themoving body.

The second engaging portion is provided, for example, in a latchingmember fixed to the housing and providing a housing space for the movingbody, the elastic portion for forward movement and the elastic portionfor reverse movement.

The elastic portion for forward movement and the elastic portion forrearward movement are fixed to the latching member while being housed inthe housing space, for example. With this arrangement, the elasticportions are elastically expanded or compressed by the forward andreverse movement of the moving body.

A third aspect of the present invention provides a lancing deviceincorporating a vacuum generating mechanism, comprising: a housing; amoving body movable relatively to the housing for forward movement of aneedle; a driving mechanism for forward movement of the moving body; ahollow pressing portion at a front end of the housing for contact with apart where a puncture is to be made; and a pump mechanism capable ofcausing a vacuum to act inside the pressing portion. The pump mechanismincludes: a moving portion capable of reciprocating in a first directionand a second direction away from the first direction; and an elasticforce generating portion storing an elastic force by the movement of themoving portion in the first direction and moving the moving portion inthe second direction by releasing the elastic force. The vacuum isgenerated by the movement of the moving portion in the first direction.

A fourth aspect of the present invention provides a method of making alancing device comprising: a housing; a moving body movable relativelyto the housing for forward movement of a needle; a driving mechanism forforward movement of the moving body; a hollow pressing portion at afront end of the housing for contact with a part where a puncture is tobe made; a pressure chamber having a volumetric capacity varied by thereciprocation of the moving portion; and a pump mechanism capable ofcausing a vacuum to act inside the pressing portion. The pump mechanismis capable of adjusting the vacuum. A maximum vacuum to be generatedinside the pressing portion is adjusted by selecting at least one of: avolumetric capacity of the pressure chamber when there is no outer forceacting on the moving portion; and a maximum volumetric capacity increasepossible in the pressure chamber when there is an outer force acting onthe moving portion.

A fifth aspect of the present invention provides a method of making alancing device comprising: a housing; a moving body movable relativelyto the housing for forward movement of a needle; a driving mechanism forforward movement of the moving body; a hollow pressing portion at afront end of the housing for contact with a part where a puncture is tobe made; a pressure chamber having a volumetric capacity varied by thereciprocation of the moving portion; and a pump mechanism capable ofcausing a vacuum to act inside the pressing portion. The pump mechanismis capable of adjusting the vacuum. The number of reciprocations to bemade by the moving portion before approaching a maximum vacuum to begenerated inside the pressing portion is adjusted by selecting an actualvolumetric capacity of the housing.

A sixth aspect of the present invention provides a pump mechanism havinga pressure chamber for generation of a vacuum in a vacuum generationchamber, comprising: a moving portion capable of reciprocating in afirst direction and a second direction away from the first direction;and an elastic force generating portion storing an elastic force by themovement of the moving portion in the first direction and moving themoving portion in the second direction by releasing the elastic force.The vacuum is generated by the movement of the moving portion in thefirst direction.

A seventh aspect of the present invention provides a sucking devicecomprising a pump mechanism for sucking a target place by generation ofa vacuum in a vacuum generation chamber. The pump mechanism is capableof adjusting the vacuum.

The pump mechanism includes for example, a moving portion capable ofreciprocating in a first direction and a second direction away from thefirst direction, and a pressure chamber having a volumetric capacityvaried by the reciprocation of the moving portion. The adjustment of thevacuum is made by changing the number of reciprocations of the movingpart in the first and the second directions.

The pump mechanism further includes for example, an elastic forcegenerating portion storing an elastic force by the movement of themoving portion in the first direction and moving the moving portion inthe second direction by releasing the elastic force. With thisarrangement, the vacuum is generated by the movement of the movingportion in the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a lancing device according to a firstembodiment of the present invention.

FIG. 2 is a sectional view of a primary portion for describing a lancingmechanism.

FIG. 3 is a perspective view of a lancet holder and a latching tab.

FIG. 4A and FIG. 4B are sectional views showing an arrangement around anoperative cap.

FIG. 5 is a sectional view for describing a pressure reducing operationin the lancing device in FIG. 1.

FIG. 6 is a sectional view for describing the pressure reducingoperation in the lancing device in FIG. 1.

FIG. 7 is a sectional view for describing a lancing operation in thelancing device in FIG. 1.

FIG. 8 is a sectional view for describing the lancing operation in thelancing device in FIG. 1.

FIG. 9 is a sectional view for describing a vacuum canceling operationin the lancing device in FIG. 1.

FIG. 10A and FIG. 10B are sectional views of a primary portion fordescribing a pressure reducing operation in a comparative example.

FIG. 11A through FIG. 11C are graphs showing a relationship between thenumber of sucking actions and vacuum.

FIG. 12 is a sectional view of a lancing device according to a secondembodiment of the present invention.

FIG. 13 is a sectional view of a lancing device according to a thirdembodiment of the present invention.

FIG. 14A and FIG. 14B are sectional views of a lancing device accordingto a fourth embodiment of the present invention.

FIG. 15 is an overall perspective view of a lancing device according toa fifth embodiment of the present invention.

FIG. 16 is a sectional view taken in lines XVI—XVI in FIG. 15.

FIG. 17 is a sectional view taken in lines XVII—XVII in FIG. 16.

FIG. 18 is an enlarged view of a primary portion in FIG. 17.

FIG. 19 is a diagram for describing actions in the portion shown in FIG.18.

FIG. 20A and FIG. 20B are sectional views for describing a pressurereducing operation in the lancing device in FIG. 15 through FIG. 17.

FIG. 21 is a sectional view for describing a lancing operation in thelancing device in FIG. 15 through FIG. 17.

FIG. 22 is a sectional view for describing a vacuum canceling operationin the lancing device in FIG. 15 through FIG. 17.

FIG. 23 is an overall perspective view of a lancing device according toa sixth embodiment of the present invention.

FIG. 24 is a sectional view taken in lines XXIV—XXIV in FIG. 23.

FIG. 25 is a sectional view of a lancing device according to a seventhembodiment of the present invention.

FIG. 26 is a sectional view of a lancing device according to an eighthembodiment of the present invention.

FIG. 27 is a sectional view of a lancing device according to a ninthembodiment of the present invention.

FIG. 28 is a sectional view of a primary portion, showing anotherapplication of the present invention.

FIG. 29 is a sectional view of a primary portion, showing anotherapplication of the present invention.

FIG. 30 is a sectional view of a primary portion, showing anotherapplication of the present invention.

FIG. 31 is a sectional view of a conventional lancing device.

BEST MODE FOR CARRYING OUT THE INVENTION

A lancing device having a vacuum creating capacity according to thepresent invention will be described with reference to FIG. 1 throughFIG. 10.

As clearly shown in FIG. 1, a lancing device A1 according to the presentembodiment comprises a lancet holder 1 for holding a lancet 10, ahousing 2 for incorporating the lancet holder 1, a pump mechanism 3, anoperative casing 4 for driving the pump mechanism 3, an operative cap 5for moving forward the lancet holder 1, and the parts and members to bedescribed below.

The lancet 10 includes, for example, a main body 10 a made of syntheticresin and a metal needle 10 b projecting out of a front end face of themain body.

The housing 2 includes a first through a third tubular portions 20A,20B, 20C. The housing 2 includes a space 21 for housing the lancetholder 1 and allowing it to reciprocate. As will be described later,when lancing with the lancing device A1, a front end of the secondtubular portion 20B is pressed onto a skin Sk to which the lancing is tobe made. Since the second tubular portion 20B can be accidentallycontaminated by the body fluid being sampled, the second tubular portion20B can be made detachable from the first tubular portion 20A to allowreplacement in a way that it can be fitted and removed like a cap. Thehousing 20A can be formed either of a single material, or of acombination of plural materials.

The operative casing 4 is for driving the pump mechanism 3, and istubular, surrounding the housing 2 and the pump mechanism 3. Theoperative casing 4 can be reciprocated longitudinally of the housing 2,in directions indicated by arrows N1, N2.

The pump mechanism 3 includes a cylinder 31 formed with a pressurechamber 30 therein, a plunger 32 slidably fitted into the cylinder 31, afirst check valve 33A, a second check valve 33B, and a return spring 34.The plunger 32 is formed integrally with a first support 21 a whichprojects out of the first tubular portion 20A from the housing 2. Theplunger 32 may of course be formed separately from the housing 20 andfixed to the first tubular portion 20A. On the other hand, the cylinder31 can reciprocate in the directions N1, N2 relatively to the housing 2and the plunger 32. The cylinder 31 has a base end (the upper end in thediagram) formed with a flange 31 a engaged by a projection 40 of theoperative casing 4. Thus, as shown in FIG. 5, when operation is made tomove the operative casing 4 downwardly in the direction N1, the cylinder31 comes down together, increasing the capacity of the pressure chamber30.

The return spring 34 is provided by e.g. a compression coil spring, andplaced between a second support 21 b which projects out of the firsttubular portion 20A of the housing 2 and a flange 31 a of the cylinder31. When the cylinder 31 moves forward or downward along with theoperative casing 4 in the direction N1, the return spring 34 iscompressed between the flange 31 a and the second support 21 b, storinga predetermined amount of elastic force to raise the cylinder 31 and theoperative casing 4.

The first check valve 33A opens and closes an air discharge port 36formed on the front end of the cylinder 31, allowing the air in thepressure chamber 30 to be discharged through the air discharge port 36and out of the pressure chamber 30, but blocking the reverse airflow.The plunger 32 is hollow, having a through hole 32 a. The plunger 32 hasa front end formed with an air intake port 35. The second check valve33B opens and closes the air intake port 35, allowing the air to comethrough the through hole 32 a of the plunger 32 into the pressurechamber 30, but blocking the reverse airflow. The through hole 32 acommunicates with the space 21 of the housing 2 via an air passage 60formed between the base end of the plunger 32 and the first supportplate 21 a of the housing 2. In the space 21, the air passage 60communicates with an open front end of the housing 2, making it possibleas will be described later that when a vacuum is created in the pressurechamber 30 of the pump mechanism 3, the created vacuum acts on the openfront end of the housing 2.

As shown in FIG. 1 through 3, the lancet holder 1 is a structureelongated in the directions N1, N2. The lancet holder 1 can be engagedwith a latching member 13 thereby urged ahead, and can be released ahead(in the direction N1 in FIG. 1 through FIG. 3) when disengaged by apressing operation on the operative cap 5. The lancet holder 1 as a holeis like a half pipe. The lancet holder 1 has a tubular tip 11 a, inwhich the lancet 10 is held. The lancet holder 1 has another end 11 bformed with a pair of projections 12. These projections 12 represent thefirst engaging portion.

The latching member 13 also is a structure elongated in the directionsN1, N2. The latching member 13 has an end formed with a second engagingportion 14. The second engaging portion 14 works as a leaf spring, andis formed with a pair of engaging projections 14 a. These engagingprojections 14 a are engaged by the pair of projections 12. The latchingmember 13 has an intermediate portion formed with an engaging piece 15for fixing the latching member 13 in the housing 2.

The latching member 13 provides a housing space 16 together with thelancet holder 1. The housing space 16 houses coil springs 17 a, 17 b inseries. These coil springs 17 a, 17 b each has an end fixed to a fixture18 formed on the latching member 13. The coil springs 17 a, 17 b eachhave another end, on the other hand, which are free with respect to thelatching member 13 but can interfere with walls 19 a, 19 b of the lancetholder 1.

Once the pair of projections 12 are engaged with the pair of engagingprojections 14 a, the coil spring 17 a comes under compression in thehousing space 16, storing an elastic force for propelling the lancetholder 1 forward. It should be noted here that the engagement of thepair of engaging projections 12 with the pair of engaging projections 14a can be achieved by pressing the lancet holder 1 into the housing 2from the front toward the base end. When the lancet holder 1 isunlatched, the elastic force of the coil spring 17 a shoots the lancetholder 1 in the direction N1. The forward movement of the lancet holder1 in the direction N1 compresses the coil spring 17 b. Therefore, afterthe lancet holder 1 has made a predetermined amount of forward movementin the direction N1, the elastic force from the coil spring 17 a pressesback the lancet holder 1 by a predetermined amount, pulling the needle10 b out of the skin Sk. The coil springs 17 a, 17 b can of course bereplaced by alternatives such as bellow-like spring, sponge and rubberfoam.

According to the lancing device A1, the coil spring 17 a for supplyingthe lancet holder with the forward force and the coil spring 17 b forsupplying the returning force are placed in line. This makes sizereduction possible around the lancing mechanism compared to a parallelplacement design of the coil springs. Further, compared to a design inwhich the coil springs are placed around the lancet holder, the springinner diameter can be smaller, and there is no need for providing aspace for the coil springs around the lancet holder. As a result, itbecomes possible to reduce the volume around the lancing mechanism, andreduce the volume of air to be pumped out by the pump mechanism 3. Thus,it becomes possible to reduce the size of the pump mechanism 3 withoutundue sacrifice, or it becomes possible to create a high level of vacuumto act on the skin.

The operative cap 5 is fitted into the operative casing 4 around thethird tubular portion 20C of the housing 2, slidably with respect to thehousing 2. The operative cap 5 includes a fixed portion 50 and anunlatching member 52 having a projection 51. An O ring 53 is placedbetween the fixed portion 50 and the unlatching member 52. Thismaintains air tightness in the housing 2, and allows the operative cap 5to move in the directions N1, N2 with respect to the housing 2 (thethird tubular portion 20C). The operative cap 5 houses a coil spring 54fitted around the third tubular portion 20C. The coil spring 54 has alower end fixed to a step 20 c of the third tubular portion 20C. Thus,when the operative cap 5 is pressed in the direction N1, the operativecap 5 is moved down while pressing the coil spring 54. During this, whenthe operative cap 5 has moved down over a predetermined distance, theunlatching member 52 acts on the engagement between the pair ofprojections 12 and the pair of engaging projections 14 a, and unlatchesthe lancet holder 1. On the other hand, when the pressing force on theoperative cap 5 is removed, the coil spring 54 moves the operative cap 5in the direction N2, to the original position.

As shown in FIG. 4A and FIG. 4B, the third tubular portion 20C is formedwith a recess 55 for allowing the air to pass through. When theoperative cap 5 is above the latch releasing position, the O ring 53 isabove the recess 55. On the other hand, when the operative cap 5 isslightly below the latch releasing position, the O ring 53 is at thelevel of the recess 55. Thus, when the operative cap 5 is pressed downfurther (in the direction N1), the recess 55 allows the air to flow fromthe outside into the housing 2, canceling the vacuum in the housing 2.

Next, a use example and function of the lancing device A1 will bedescribed.

First, if it is preferable to put the skin Sk under a vacuum before thelancet 10 is pushed into the skin Sk, as shown in FIG. 5, the operativecasing 4 is pressed in the direction N1 relatively to the housing 2while the front end of the housing 2 is held onto the skin Sk. In thisoperation, the cylinder 31 moves down relatively to the plunger 32,increasing the capacity of the pressure chamber 30 thereby creating avacuum in the pressure chamber 30, which causes the second check valve33B to open. Then, the air in the space 21 of the housing 2 flows intothe pressure chamber 30 through the air passage 60 and the through hole32 a, creating a vacuum in the housing 2, which acts on the skin Sk.

After the operative casing 4 has been pressed down, it is easy to letthe operative casing 4 and the cylinder 31 move back to their originalpositions using the elastic force from the spring 34. As shown in FIG.6, when the operative casing 4 and the cylinder 31 are raised back inthe direction N2, the capacity of the pressure chamber 30 decreases,causing the second check valve 33B to close and the first check valve33A to open. Thus, when the cylinder 31 is moved back to the originalposition, it is possible to let the air in the pressure chamber 30escape appropriately through the air discharge port 36 while maintainingthe vacuum in the space 21 of the housing 2.

As described, if a vacuum in the space 21 of the housing 2 can bemaintained when the operative casing 4 and the cylinder 31 are movedback to their original positions, it becomes possible when the operativecasing 4 is further pressed down again, to increase the level of vacuumin the space 21 of the housing 2, thereby increasing the negativepressure (decrease the absolute air pressure value) in the space 21. Asa result, according to the lancing device A, it is possible toappropriately adjust the level of vacuum acting on the skin Sk, byincreasing or decreasing the number of pushing operations.

Next, in order to drive the lancet 10 into the skin Sk, as shown in FIG.2 and FIG. 7, the operative cap 5 is pressed down in the direction N1 torelease the latch on the lancet holder 1. As shown in FIG. 2 and FIG. 8,this allows the coil spring 17 a to move the lancet holder 1 forward,causing the lancet 10 to stick into the skin Sk. Once the lancet 10 isdriven into the skin Sk, the spring 17 b (See FIG. 2) thrusts the lancetholder 1 back, thereby pulling the lancet 10 out of the skin Skimmediately. Since the skin Sk is under the vacuum created earlier,bleeding is promoted from the place pricked by the lancet 10. This helpsbleeding to be a relatively large level while making the depth oflancing by the lancet 10 as small as possible.

As shown in FIG. 4A and FIG. 4B, when the operative cap 5 is furtherpressed down in the direction N1, the space 21 in the housing 2communicates with the outside via the recess 55 of the operative cap 5,allowing the air to come inside the space 21 through the recess 55.Thus, the pressure in the space 23 comes back to a normal atmosphericpressure. Such an operation makes very easy to release the housing 2from the skin Sk.

According to the lancing device A1, the vacuum acting on the skin Skcannot be released easily unless the operative cap 5 is pressed furtherafter the operative cap 5 is first operated to drive the lancet 10 intothe skin Sk. This arrangement makes sure that the vacuum acting on theskin Sk is not mistakenly lost, that the skin Sk is properly bulged andstimulated for improved blood flow before the lancet 10 is driven.Further, both driving of the lancet 10 and releasing of the vacuum canbe made continuously by pressing the operative cap 5, resulting insimplified operation of these steps.

According to the use example described above, a vacuum is first createdin the space 21 of the housing 2, and then the lancet 10 is driven intothe skin Sk. Alternatively, according to the lancing device A1, thesteps maybe reversed. Namely, the sequence may be that the operative cap5 is pressed to drive the lancet 10 into the skin first, and then theoperative casing 4 is operated to create a vacuum on the place prickedby the lancet 10. This sequence too can promote bleeding from the placepricked by the lancet 10, by means of vacuum. As described, the lancingdevice A1 is convenient in that the user can select whether the vacuumshould be created before or after the lancet 10 is driven into the skinSk. Further, according to the lancing device A1, when the operativecasing 4 is reciprocated in order to create a vacuum, the front end ofthe housing 2 gives a massage to the skin Sk, potentially resulting infurther improvement in the blood flow in the skin Sk.

According to the lancing device A1, a vacuum is created when theoperative casing 4 is pressed down against the elastic force from thereturn spring 34. Therefore, the vacuum can be created right away. Inaddition, there is another advantage as follows: Specifically, the pumpmechanism could have been different from the one according to thepresent embodiment, and can be as shown in FIG. 10A, in which thecapacity of a pressure chamber 30′ decreases when a plunger 32′ ispressed down against an elastic force R from a spring 34′. Thereafter,as shown in FIG. 10B, the capacity of the pressure chamber 30′ increasesto create a vacuum when the plunger 32′ is raised back into the positionby the elastic force R of the spring 34′. A challenge in such anarrangement however, is that the elastic force R from the spring 34′,must be able to not only raise the plunger 32′ against friction betweenthe plunger 32′ and the pump mechanism 33′ but also overcome theatmospheric pressure in order to create a vacuum in the pressure chamber30′. In other words, a total of the two forces is required. The forcerequired to press the plunger 32′ is greater than the elastic force R ofthe spring 34′.

On the contrary, according to the arrangement offered by the presentembodiment, a vacuum is not created in the pressure chamber 30 when thereturn spring 34 comes back into the original state after it iscompressed. Therefore, the return spring 34 should only be able toprovide a force necessary to overcome a friction between the plunger 32and the cylinder 31 for raising the cylinder 31 back into the originalposition. Therefore, the return spring 34 according to the presentembodiment can have a spring constant smaller than that of the spring34′ shown in FIG. 10A and FIG. 10B. As a result, according to thepresent embodiment, the amount of force necessary for pressing down thecylinder 31 and the operative casing 4 against the elastic force fromthe return spring 34 can be accordingly smaller, leading to improvedoperability.

According to the lancing device A1, the vacuum created in the housing 2can be adjustable. A maximum level of the vacuum and the number ofreciprocations of the operative casing 4 necessary for approaching theset maximum level of vacuum can be selected on the basis of experimentto be described next.

The inventor et al studied a relationship between the number ofreciprocations of the operative casing and pressure change in thehousing 2. Results of the study are shown in FIG. 11A through FIG. 11C.Each of the graphs shows results of an experiment under differentconditions. In the experiment, two values were fixed; dead capacity V2of the pressure chamber 30 (the volumetric capacity of the pressurechamber 30 under normal conditions), and capacity V3 (a maximumvolumetric capacity increase in the pressure chamber 30) obtained bysubtracting the dead capacity V2 from a maximum capacity of the pressurechamber 30 achieved. On the other hand, actual volumetric capacity ofthe housing 2 (i.e. the space occupied by a gaseous body (includinghowever, the space of the air passage 60 shown in FIG. 1, and thethrough hole 32 a of the plunger 32) was varied. V1 through V3 werecreated in tubular columns of the same diameter, and adjusted in termsof the height. Settings used in each of the first through the thirdembodiments are shown in the following tables 1 through 3 respectively.

Capacity (cm³) V1 (Actual V2 V3 Symbols in Capacity (Dead (Max Increasethe Graphs of Housing) Capacity) in Capacity) Embodiment 1 ◯ 13.26650.785 0.72597 (FIG. 11A) ● 6.63325 Δ 3.97995 ▴ 2.6533 □ 1.32665Embodiment 2 ◯ 13.2665 0.785 1.45194 (FIG. 11B) ● 6.63325 Δ 3.97995 ▴2.6533 □ 1.32665 Embodiment 3 ◯ 13.2665 0.785 2.1779 (FIG. 11C) ●6.63325 Δ 3.97995 ▴ 2.6533 □ 1.32665

As understood from FIG. 11A through FIG. 11C, the number of suckingoperations necessary for approaching the maximum level of vacuum in thehousing 2 can be decreased if the actual capacity V1 of the housing 2 isdecreased. Further, a common tendency can be understood from all of thegraphs. Specifically, the larger the actual capacity V1 of the housing2, the greater the number of pumping actions will be needed to approachthe maximum level of vacuum in the housing 2. In other words, when it isdesirable to create a relatively high level of vacuum by a singlepumping action, the actual capacity V1 of the housing 2 should be madesmall. On the other hand, when gradual increase to a target level ofvacuum is desirable, the actual capacity V1 of the housing 2 should bemade large. If the maximum capacity increase V3 is large, the maximumlevel of vacuum is large, whereas if the maximum capacity increase V3 ofthe pressure chamber 30 is small, the maximum level of vacuum is small.Thus, by selecting the maximum capacity increase V3 in the pressurechamber 30, the maximum level of vacuum achievable in the housing 2 canbe adjusted. Also, by selecting the actual capacity V1 of the housing 2,the number of pumping actions necessary for approaching the maximumlevel of vacuum can be adjusted.

It should be noted here however, that the results shown in FIG. 11Athrough FIG. 11C are those when the dead capacity V2 of the pressurechamber 30 was constant. Thus, it is also possible to adjust the maximumlevel of vacuum by varying V2 while having V3 fixed.

Next, a lancing device A2 according to a second embodiment of thepresent invention will be described with reference to FIG. 12. In FIG.12, members and elements identical with or similar to those in thelancing device A1 described already are given the same alphanumericcodes and their description will not be repeated here.

As shown in FIG. 12, the lancing device A2 has a different lancingmechanism from the one used in the lancing device A1. This lancingmechanism includes a lancet holder 1A, an operative cap 5A, a forwardpropelling spring 17 a and a rearward propelling spring 17 b.

In the lancing device A2, the lancet holder 1A includes a plurality oflatching pawls 12A. These latching pawls 12A engage with steps 14A inthe housing 2A. The engagement with the steps 14A by the latching pawls12A can be achieved by pushing the lancet holder 1A from the front endside toward the base end side of the housing 2A.

The operative cap 5A is slidably fitted into an operative casing 4. Tothe operative cap 5A, a push rod (an unlatching portion) 50A is hooked.The push rod 50A is slidably fitted, while maintaining air tightnesswith respect to the third tubular portion 20C of the housing 2A. Thepush rod 50A has an outer circumferential wall provided with a recess55A serving as an air passage. Although the recess 55A can communicatewith the outside of the housing 2A, the communication with the space 21of the housing 2A is not established under normal conditions. However,when the operative cap 5A is pressed by an appropriate amount, therecess 55A opens up in the space 21, establishing the communication withthe space 21 via the recess 55A.

The forward propelling spring 17 a has an upper end fixed to the pushrod 50A and a lower end fixed to the lancet holder 1A. The forwardpropelling spring 17 a is compressed when the latching pawls 12A areengaged with the steps 14 a in the housing 2A.

On the other hand, the rearward propelling spring 17 b has an upper endfixed to the lancet holder 1A and a lower end fixed to a steps 20 b ofthe housing 2A (the second tubular portion 20B). The spring 17 b iscompressed when the lancet holder 1A moves forward.

According to the lancing mechanism described above, when the operativecap 5A is pressed in the direction N1, the push rod 50A hooked to theoperative cap 5A moves forward while compressing the forward propellingspring 17 a, thereby compressing the latching pawls 12A. When pressed bythe push rod 50A, the latching pawls 12A are disengaged (unlatched) fromthe steps 14 a. When released from the engagement, the lancet holder 1is shot forward in the direction N1 by the elastic force from the coilspring 17 a. Also, after moving forward by a predetermined amount towardthe tip of the housing 2A, the lancet holder 1A is moved back by apredetermined amount by an elastic force from a spring 17 b provided inthe housing 2A.

When the operative cap 5A is further pressed, the recess 55A of the pushrod 50A makes the air passage for the space 21 to communicate with theoutside. Therefore, any vacuum which may have been created in thehousing 2 by the pump mechanism 3 can be cancelled by pressing theoperative cap 5A.

Next, a lancing device A3 according to a third embodiment of the presentinvention will be described with reference to FIG.13. In this diagram,members and elements identical with or similar to those in the lancingdevice A1 and A2 described already are given the same alphanumeric codesand their description will not be repeated here.

As shown in FIG. 13, the lancing device A3 has a pump mechanism 3Aperpendicular to the direction N1 or the direction in which the lancet10 moves. Accordingly, an operative casing 4A includes a first portion41 incorporating a lancet holder 1A and others, and a second portion 42extending perpendicularly (in a direction N4) from the first portion 41and incorporating the pump mechanism 3A.

The pump mechanism 3A uses basically the same arrangement as in thelancing device A1. Specifically, the pump mechanism 3A includes aplunger 32A having an air intake port 35, a cylinder 31A having an airdischarge port 36 and forming a pressure chamber 30 together with theplunger 32A, check valves 33A, 33B, and a return spring 34.

A difference however, is that the cylinder 31A is fixed to an operativeportion 59. The operative portion 59 projects out of an opening 42 aformed in a second portion 42 of an operative casing 4A. On the otherhand, the plunger 32A is fixed to the second portion 42 of the operativecasing 4A. The plunger 32A is connected to a housing 2A via a tube C.Thus, the inside of the pressure chamber 30 communicates with the insideof the housing 2A via a through hole of the plunger 32A and via the tubeC.

In the pump mechanism 3A, when a force is applied on the operativeportion 59 in a direction indicated by an arrow N3, the cylinder 31Amoves in the direction N3 to increase the capacity of the pressurechamber 30. In this movement, the check valve 33B opens to allow the airin the housing 2A to flow through the tube C and into the pressurechamber 30, causing a vacuum in the housing 2A. At the same time, anelastic force is stored in the return spring 34. On the other hand, whenthe force applied in the direction N3 is removed, the elastic force fromthe return spring 34 moves the cylinder 31A in the direction N4. In thismovement, the check valve 33A opens to discharge the air from thepressure chamber 30 through the air discharge port 36, reducing thecapacity of the pressure chamber 30.

Next, a lancing device A4 according to a fourth embodiment of thepresent invention will be described with reference to FIG. 14A and FIG.14B. In these figures, members and elements identical with or similar tothose in the lancing devices A1 through A3 described already are giventhe same alphanumeric codes and their description will not be repeatedhere.

In the lancing device A4, as shown in FIG. 14A and FIG. 14B, a vacuumcan be created by reciprocation of an operative lever 59A in directionsindicated by arrows N5, N6. Again in this embodiment, the lancing deviceA4 includes a pump mechanism 3B which is similar to those used in thelancing devices A1 through A4. However, the actual arrangement used forthe pump mechanism is basically the same as in the lancing device A1.Specifically, the pump mechanism 3B includes a cylinder 31B, a plunger32B, a return spring 34, and check valves (not illustrated).

An operative casing 4B includes two supports 43A, 43B. The support 43Apivotably supports the operative lever 59A. The support 43A has athrough hole 43 a. The through hole 43 a allows the cylinder 31B to movein the directions N1, N2, and guides the movement of the cylinder 31B.The cylinder 31B has an upper end serving as a stopper. Between thisstopper and the support 43A, a spring 34 is provided around the cylinder31B. On the other hand, the support 43B holds the plunder 32B. Thecylinder 31B has an upper end linked to the operative lever 59A by alink member 59 a. Though not illustrated, the inside of the housing (notillustrated) communicates with the inside of the plunger 32B via apassage provided in the support 43B.

In the lancing device A4, the operative lever 59A is moved in thedirection N5 to move the cylinder 31B in the direction N1 thereby toincrease the capacity of the pressure chamber. This allows the air inthe housing to flow into the pressure chamber, creating a vacuum in thehousing. In this step, the return spring 34 stores an elastic force. Onthe other hand, when the force acting on the operative lever 59A isremoved, the elastic force from the return spring 34 moves the cylinder31B in the direction N2, causing the link member 59 a to move theoperative lever 59A in the direction N6. In this step, the air isdischarged from the pressure chamber, and the capacity of the pressurechamber decreases.

Next, a lancing device A5 according to a fifth embodiment of the presentinvention will be described with reference to FIG. 15 through FIG. 22.In these figures, members and elements identical with or similar tothose in the lancing devices A1 through A4 described already are giventhe same alphanumeric codes and their description will not be repeatedhere.

The lancing device A5 according to the present embodiment includes ahousing 2C, which incorporates a pump mechanism 3C driven by anoperative casing 4C, and a lancing mechanism actuated by an operativecap 5C. The housing 2C is provided by three sleeves 20CA through 20CCconnected together.

As shown in FIG. 16, the pump mechanism 3C includes a pressure chamberprovided by a cylinder 31C and a plunger 32C, and a first and a secondcheck valves 33A, 33B.

The operative casing 4C is fitted around the housing 2C and canreciprocate axially in directions N1, N2 relatively to the housing 2C.When the operative casing 4C is pressed down relatively to the housing2C, a spring 34 moves the operative casing 4C back into the originalposition.

The cylinder 31C is fitted into an upper portion (ahead) of the housing2C and can reciprocate within a predetermined stroke range. Above thecylinder 31C, an operative cap 5 projects out of the upper end of anouter cylinder 2, to allow a pressing operation. When the operative cap5C is pressed down, the cylinder 31C also comes down. A spring 54C isprovided below the cylinder 31C. The coil spring 54 moves the cylinder31C back to the original position after it is lowered.

The plunger 32C is fitted in and can reciprocate with respect to thecylinder 31C. As clearly shown in FIG. 17, the plunger 32C includes apair of arms 37 for connection with an upper portion of the operativecasing 4C. Therefore, when the operative casing 4C is reciprocated indirections N1, N2, the cylinder 31C also reciprocates in the cylinder31C.

The check valve 33A opens and closes an air discharge port 36 and isattached to the plunger 32C. The check valve 33A allows the air to flowfrom the pressure chamber 30 to the outside, but blocks the air flowingfrom the outside into the pressure chamber 30.

The cylinder 31C has a bottom provided with an air intake port 35 forallowing the air inside the housing 2C to flow into the pressure chamber30. The housing 2C includes a series of passages connecting the airintake port 35 to the inside of the front end of the housing 2C. Morespecifically, the air intake port 35 communicates with the inside of thefront end of the housing 2C via through holes formed in a first and asecond pushers 71A, 71B to be described later, a plurality of slits 72provided at an upper portion of a lancet holder 1C, and a gap 74 betweena step 73 of the housing 2C and the lancet holder 1C.

The check valve 33B opens and closes the air intake port 35. The checkvalve 33B allows the air to flow from the outside of the pressurechamber 30 into the pressure chamber 30, but blocks the air flowing fromthe pressure chamber 30 to the outside.

As clearly shown in FIG. 18, the lancing mechanism moves the lancetholder 1C toward the front end. The lancing mechanism includes a sleeve70, and the first and the second pushers 71A, 71B which can reciprocatetherein. The sleeve 70 is fixed in the housing 2C and below the cylinder31C. Close to a lower end of the sleeve 70, a pair of holes 75 is formedfor a pair of latching pawls 12C to engage. The lancet holder 1C has anupper portion incorporating a coil spring 17 a having an upper endcontacting the second pusher 71B. The lancet holder 1C can be latched tothe sleeve 70 by the engagement between the latching pawls 12C and theholes 75 while the coil spring 17 a is compressed.

The first pusher 71A, connected to the bottom of the cylinder 31C, canreciprocate with the cylinder 31C. The first pusher 71A has a lower endfitted into the sleeve 70. The second pusher 71B, which has an upper endfitted into the sleeve 70, can reciprocate in the sleeve, and iscontacted to the bottom of the first pusher 71A by an elastic force fromthe coil spring 17 a. The second pusher 71B is an example of theunlatching portion according to the present invention, and has a pair ofprojections 72 a located above the respective engaging pawls 12C of thelancet holder 1C. Each of the projections 72 a and the engaging pawls12C is formed with a predetermined tapered surface to fit each other.When the projections 72 a come down below their position shown in FIG.18, the projections 72 a presses the respective engaging pawls 12C todeform inwardly, releasing the engagement between the engaging pawls 12Cand the sleeve 70. The lancet holder 1C is surrounded by a coil spring17 b. The coil spring 17 b moves the lancet holder 1C in the directionN2 after a puncture is made.

The first pusher 71A is fitted with an O ring 76 made of rubber forexample, to keep air tightness between the first pusher 71A and theinner wall of the sleeve 70. However, the inner wall of the sleeve 70has a step 77, so that the amount of resistance changes as the operativecap 5C is pressed to move the first pusher 71A down. More specifically,an inner diameter D1 of an upper portion of the sleeve 70 is slightlylarger than the inner diameter D2 of the lower portion. During thedownward movement of the O ring 76 moving with the first pusher 71A,when the second pusher 71B unlatches the engagement between the engagingpawls 12C and the sleeve 70, the O ring 76 come right at the step 77. Asclearly shown in FIG. 19, the first pusher 71A can come as far as the Oring 76 has passed the portion having the diameter D2, upon which theair tightness between the first pusher 71A and the sleeve 70 is lost.

The lancet holder 1C has a tip provided with an assisting cap 78surrounding a lancet 10. When the lancet holder 1C moves forward, afront face 78 a of the assisting cap 78 makes contact with the skin,allowing only a portion of the lancet 10 projecting out of the frontface 78 to stick into the skin. With this arrangement, the assisting cap78 can be made movable axially of the lancet holder 1C so that theamount of projection S of the lancet 10 out of the assisting cap 78 canbe adjusted. Then, the depth to which the lancet 10 is driven can bevaried freely. According to the present invention, however, it is notessential to include such means. Inside the front end of the housing 2C,a generally tubular guide 79 is provided for guiding the forwardmovement of the assisting cap 78. The guide 79 and a front end portionof the housing 2C can be transparent so that bleeding from the skin canbe visually observed.

Next, a use example and function of the lancing device A5 having theabove arrangement will be described.

As shown in FIG. 16 and FIG. 17, when the lancing device A5 is used, thelancet holder 1C fitted with the lancet 10 is latched to the sleeve 70.Next, as shown in FIG. 15, the front end of the housing 2C is held ontothe skin. If a vacuum is desired, the operative casing 4C is moved upand down. The operative casing 4C is easy to grip, and has a goodoperability because the coil spring 34 raises the operative casing 4Cafter the operative casing 4C has been pressed down.

As shown in FIG. 20, when the operative casing 4C moves down in thedirection N1, the plunger 32C comes down also. In this step, the checkvalve 33B is closed whereas the check valve 33A is open, allowing smoothdischarge of the air from the pressure chamber 30 to the outside of thehousing 2C via the air discharge port 36. On the contrary, as shown inFIG. 20B, when the operative casing 4C moves up in the direction N2, theplunger 32C also comes up, increasing the capacity of the pressurechamber 30 thereby creating a vacuum in the pressure chamber 30. In thisstep, the check valve 33A is closed whereas the check valve 33B is open.Therefore, a vacuum also is created inside the front end of the housing2C and acted on the skin.

Following the above operation, if the operative casing 4C is continuedto be reciprocated, the check valve 33B, which closes when the plunger32C moves down, properly maintains the vacuum in the inside of the frontend of the housing 2C. Thus, it is possible to gradually increase thenegative pressure (decrease the absolute air pressure value) inside thepressure chamber 30 and the front end of the housing 2C for eachreciprocation of the operative casing 4C. As a result, according to thelancing device A5, it is possible to appropriately adjust the level ofvacuum acting on the skin, by increasing or decreasing the number ofreciprocating operations.

Next, in order to drive the lancet L, the operative cap 5C is presseddown using a finger. In this operation, the cylinder 31C and the firstand the second pushers 71A, 71B move down relatively to the housing 2C,causing the second pusher 71B to press each of the engaging pawls 12C ofthe lancet holder 1C, thereby unlatching the lancet holder 1C from thesleeve 70. Then, as clearly shown in FIG. 21, the lancet holder 1C isshot toward the front end opening of the housing 2C, in the direction N1by an elastic force from the coil spring 17 a, causing the lancet 10 tostick into the skin. From this state, if the user is about to press theoperative cap 5C further, the O ring 76 of the first pusher 71A shown inFIG. 18 moves in the sleeve 70, from a place having the diameter D1 to aplace having the diameter D2, to generate a greater resistance. Thus,based on such an increase in the resistance, the user can properlypercept the completion of the forward movement of the lancet 10. Oncethe lancet 10 is driven into the skin, the coil spring 17 b moves backthe lancet holder 1C by an appropriate amount, thereby pulling thelancet 10 out of the skin.

As shown in FIG. 22, when the operative cap 5C is further pressedthereafter, then as shown in FIG. 18, the O ring 76 comes down in thesleeve 70, to pass the place having the inner diameter D2. This breaksthe air tightness in the passage, from inside the front end of thehousing 2C to the air discharge port 36 of the cylinder 31C, and theatmospheric pressure comes inside the front end of the housing 2C,allowing the housing 2C to be removed easily from the skin.

According to the lancing device A5, a vacuum acting on the skin cannotbe released unless the operative cap 5C is pressed further after theoperative cap 5C is first operated to drive the lancet 10 into the skin.This arrangement makes sure that the vacuum acting on the skin is notmistakenly lost before the lancet 10 is driven. Therefore, a propersequence of operations is assured; the skin is properly bulged andstimulated by partial vacuum for improved blood flow before the lancet10 is driven. Further, both driving of the lancet 10 and releasing ofthe partial vacuum can be made continuously by pressing the operativecap 5C, resulting in simplified operation for these steps.

According to the use example described above, a vacuum is first createdin the housing 2C, and then the lancet 10 is driven into the skin.Alternatively, according to the lancing device A5, the steps may bereversed. Namely, the sequence may be that the operative cap 5C ispressed to drive the lancet 10 into the skin first, and then theoperative casing 4C is operated to create partial vacuum on the placepricked by the lancet 10. This sequence too can promote bleeding fromthe place pricked by the lancet 10, by means of vacuum. As described,the lancing device A5 is convenient in that the user can select whetherthe partial vacuum should be created before or after the lancet 10 isdriven into the skin. Further, according to the lancing device A5, whenthe operative casing 4C is reciprocated in order to create a vacuum, thetip of the housing 2C gives a massage to the skin, potentially resultingin further improvement in the blood flow in the skin.

According to the lancing device A5, the cylinder 31C for creating avacuum is placed inside the housing 2C. With this arrangement, when theoperative cap 5C is pressed, the cylinder 31C helps the unlatchingaction to release the lancet holder 1C. Further, since the air dischargeport 36 and the check valve 33A are provided in the plunger 32C, thesecomponents do not project out of the cylinder 31C. Further, the passagesfrom inside the front end of the housing 2C to the air intake port 35are provided by through holes formed through the center of the first andthe second pushers 71A, 71B. Thus, according to the lancing device A5,space-efficient, rational assembly of components is achieved, makingpossible to slim down the overall size.

The return spring 34 of the plunger 32C is provided in a space-efficientmanner between the operative casing 4C and the housing 2C, and there isno return springs or other components placed in the pressure chamber 30.Therefore, according to the lancing device A5, as compared to a case inwhich the pressure chamber 30 incorporates a return spring or the like,the effective volumetric capacity of the pressure chamber 30 can beincreased, making it possible to create a high level of vacuum with asingle reciprocating stroke of the plunger 32C. This helps decrease thenumber of reciprocating strokes of the operative casing 4C and theplunger 32C necessary for creating a given level of vacuum.

FIG. 23 and FIG. 24 show a lancing device according to a sixthembodiment of the present invention. In these figures, members andelements identical with or similar to those in the lancing devices A1through A5 described already are given the same alphanumeric codes andtheir description will not be repeated here.

The A6 includes an operative casing 4C having a front end outer wallformed with a pair of helical long holes 49. A housing 2C includes asecond tube 20B having a front end outer wall formed with projections 29to correspond to the long holes 49 respectively. When the operativecasing 4C is moved up and down in the directions N1, N2, the projections29 guided in the long holes 49 make a sleeve 20CB rotate in a directionindicated by an arrow Nf.

According to such an arrangement, when the operative casing 4C is movedup and down for creating a vacuum inside the front end of the housing2C, the sleeve 20CB contacting the skin makes rotating actionsimultaneously, giving a massage to the skin. Therefore, bleeding ispromoted not only by the partial vacuum in the housing 2C but also bythe massaging action, making it easy to take blood samples from placeswhere it is difficult to cause bleeding.

FIG. 25 through FIG. 27 show lancing devices according to a seventh to aninth embodiments of the present invention. In the lancing devices A7through A9 shown in these figures, a pump mechanism 3E and a housing 2Eare placed side by side.

In the lancing device A7 shown in FIG. 25, communication with thehousing 2E is achieved via a passage 60E provided in the cylinder 31E.On the other hand, in the lancing device A8 shown in FIG. 26, a plunger32E communicates with the housing 2E via a tube C. In these lancingdevices A7, A8, vertical reciprocation of an operative casing 4E causesthe plunger 32E to move and thereby varies the capacity of the pressurechamber 30. With this arrangement, the level of vacuum in the housing 2Ecan be adjusted by the number of reciprocations of the operative casing4E.

The A9 shown in FIG. 27 includes an operative button 8 which serves adifferent purpose from an operative cap 5E which is for making apuncture. When the operative button 8 is pressed in the direction N1,the plunger 32E moves downward to decrease the capacity of the pressurechamber 30. According to the lancing device A9, the level of vacuum inthe housing 2E can be adjusted by the number of reciprocations made tothe operative button 8.

The lancing device according to the present invention is not limited tothose embodiments described here above, and specifics of the members andcomponents can be varied in many ways.

For example, the first and the second check valves may be of a typedifferent from the one used in the embodiments. Further, a plurality ofthese valves may be used, and there is no limitation to the number ofthe valves.

The present invention is applicable not only to the type of lancingdevice including a lancet holder that holds a lancet, but also to othertypes, such as shown in FIG. 28, in which a moving body 1F, whichcorresponds to the lancet holder, integrally includes a needle 10 b.

Further, the present invention is also applicable to a type shown inFIG. 29, in which a lancet 10 is held in a cover (sleeve) 20GB, and thelancet 10 (needle 10 b) is moved by a thrust from a hammer 1G. Themovement of the hammer 1G is actuated by the latch mechanism describedearlier. According to this arrangement, when the hammer 1G is unlatched,the hammer 1G moves toward the front end, shooting the lancet 10 towardthe front end to drive the needle 10 b into the skin. Upon making thepuncture, an elastic force from the coil spring 17 b moves the lancet 10in the reverse direction, pulling the needle 10 b out of the skin.

Alternatively to coil springs, leaf spring 17 b′ may be used as shown inFIG. 30, so that the elastic force from the leaf spring 17 b′ is used topull the needle 10 b of the lancet 10 once the puncture is made. Theleaf spring 17 b′ may be integral with the cover 20GB, or may be formedseparately from the cover 20GB and then integrated with the cover 20GB.

The pump mechanism according to the present invention is not limited tothose provided by combination of the cylinder and the plunger, but caninclude the diaphragm type and other types of pump mechanisms. The drivemechanism for the lancet holder (moving body) according to the presentinvention can be anything as long as the lancet holder (moving body) canbe moved forward toward the front end, and therefore can have mechanismsdifferent from the one used in the embodiments.

1. A lancing device incorporating a vacuum generating mechanism,comprising: a housing; a moving body movable relatively to the housingfor forward movement of a needle; a driving mechanism for forwardmovement of the moving body; a hollow pressing portion at a front end ofthe housing for contact with a part where a puncture is to be made; anda pump mechanism capable of causing a vacuum to act inside the pressingportion, wherein the pump mechanism is capable of adjusting the vacuum;and wherein the pump mechanism includes: a moving portion capable ofreciprocating in a first direction and a second direction opposite tothe first direction; a pressure chamber capable of communicating with anoutside of the pressing portion via a discharge port and capable ofcommunicating with an inside of the pressing portion via an intake port,the pressure chamber having a volumetric capacity varied by thereciprocation of the moving portion, a first check valve capable ofopening and closing the discharge port, the first check valve openingthe discharge port when the volumetric capacity of the pressure chamberdecreases, and the first check valve closing the discharge port when thevolumetric capacity of the pressure chamber increases, and a secondcheck valve capable of opening and closing the intake port, the secondcheck valve opening the intake port when the volumetric capacity of thepressure chamber increases, and the second check valve closing theintake port when the volumetric capacity of the pressure chamberdecreases.
 2. The lancing device according to claim 1, wherein theadjustment of the vacuum is made by changing the number ofreciprocations of the moving portion in the first and the seconddirections.
 3. The lancing device according to claim 1, wherein thepressure chamber is provided by a combination of a cylinder and aplunger, the moving portion causing one of the plunger and the cylinderto reciprocate relatively to one another.
 4. The lancing deviceaccording to claim 3, wherein the discharge port and the first checkvalve are provided in the cylinder.
 5. The lancing device according toclaim 3, wherein the discharge port and the first check valve areprovided in the plunger direction.
 6. The lancing device according toclaim 3, wherein the driving mechanism includes: a first engagingportion provided on the moving body; an elastic portion for urging themoving body in the forward direction; a second engaging portionengageable with the first engaging portion for latching the moving bodyin the housing; a lancing operation member having at least a partthereof exposed to outside of the housing; and an unlatching portion toact on the engagement between the first and the second engaging portionsfor unlatching the moving body upon operation of the lancing operationmember.
 7. The lancing device according to claim 6, wherein theunlatching portion is fixed to the lancing operation member.
 8. Thelancing device according to claim 6, wherein the cylinder is movablerelatively to the housing.
 9. The lancing device according to claim 8,wherein the cylinder is fitted reciprocably in the housing.
 10. Thelancing device according to claim 6, wherein the inside of the pressingpotion communicates with an outside of the housing when the lancingoperation member is operated further, after the moving body isunlatched.
 11. The lancing device according to claim 6, wherein thelancing operation member is operable under a smaller resistance beforethe unlatching of the moving body than after.
 12. The lancing deviceaccording to claim 1, wherein vacuum generation by the pump mechanism isselectable either before or after the moving body is moved forward. 13.The lancing device according to claim 1, wherein the pressure chamber isprovided outside of the housing and communicates with an inside of thehousing.
 14. The lancing device according to claim 1, wherein thepressure chamber is provided inside the housing.
 15. The lancing deviceaccording to claim 1, wherein the pump mechanism further includes anelastic force generating portion storing an elastic force generated bythe movement of the moving portion in one direction and moving themoving portion in an opposite direction by releasing the elastic force,and wherein the vacuum is generated by the movement of the movingportion in said one direction.
 16. A lancing device incorporating avacuum generating mechanism, comprising: a housing; a moving bodymovable relatively to the housing for forward movement of a needle; adriving mechanism for forward movement of the moving body; a hollowpressing portion at a front end of the housing for contact with a partwhere a puncture is to be made; and a pump mechanism capable of causinga vacuum to act inside the pressing portion; wherein the pump mechanismis capable of adjusting the vacuum; wherein the pump mechanism includes:a moving portion capable of reciprocating in a first direction and asecond direction away from the first direction; and a pressure chamberhaving a volumetric capacity varied by the reciprocation of the movingportion; wherein the lancing device further comprises a pressurereducing operation member for movement of the moving portion; whereinthe pressure reducing operation member reciprocates with respect to thehousing; and wherein the pressing portion is rotated about an axisthereof by the reciprocating action of the pressure reducing operationmember with respect to the housing.
 17. The lancing device according toclaim 16, further comprising an elastic portion urging the movingportion for returning reverse movement, the elastic portion beingoutside of the pressure chamber.